| 摘要 |
PROBLEM TO BE SOLVED: To donate superb mechanical strength and dimensional stability and improve the durability to environmental changes by forming a laminated polyester film of two or more layers of a lamination structure and also forming at least one layer of a polyester and a polyimide which are composed mainly of ethylene terephthalate units. SOLUTION: The laminated polyester film is formed of a two or more-layer lamination structure, at least one layer being formed of a polyester and a polyimide which are composed mainly of ethylene terephthalate units. The layer formed of the polyester and the polyimide shows 90-150 deg.C extrapolated glass transition starting temperature and the content of the polyimide is 1-50 wt.%. Besides, the polyimide is added in the form of a polyester imide. In addition, the sum of the Young's modulii in the longitudinal and the width direction of the laminated polyester film is set to be 10-25 (GPa) and the coefficient of thermal shrinkage of the laminated polyester film in at least either of the longitudinal or the width direction at 100 deg.C for 30 min. is set to be 0.01-2.0%. Further, the thickness of the laminated polyester film is preferably 1,000 μm or less. |
